diabloridr

It's more likely the small stoker compartments seen on older tandems were a result of the limited tubing choices and the design knowledge available. Small stoker compartments were used to avoid overly "whippy" tandems. As tandem manufacturers gained experience (and had better design tools and tubing choices available), options for stoker compartment size improved.

When we were specifying our 1999 Co-Motion Speedster, we opted to increase the stoker compartment by 2 inches from the default geometry as my stoker used an unusually narrow Cinelli handlebar at the time. Moving the bar backwards was necessary to avoid interference with my hips.

By the time we bought our Co-Motion Macchiato in 2017, the off-the-shelf stoker compartment length was the same as our previous custom geometry.

Interestingly, perhaps the longest stoker compartments I can remember were on the Hooker time trial tandems from the 1990's. These tandems allowed the stokers to achieve a low, flat, and narrow position tucked behind the captain.

cyccommute 

I’m a bit sorry about that…but only a bit. I get passionate about bikes for small riders because of my long experience with a small rider. Those of us of average height (male or female) have few problems with bike fit, although there’s lots of electrons killed in the discussion of proper fit. But when it comes to small riders, most people are of the mind that “it can be made to work” even if it can’t. By all means test some tandems but do so with your stoker as your primary concern.

I do have a new hypothesis…I ponder while I wander…on why people keep putting small riders on the wrong size bike. That small bikes aren’t available is a large part of the problem but I’m beginning to think that most bike shops that deal with small people are dealing with children. They will put a child on a bike that is a bit too large so that they can “grow into it”. When a small person (usually a woman) comes along, they kick into kid mode and figure that the rider with “grow into the bike”. It’s not necessarily a conscious thought but due to them dealing with more kids than small people.

Carbonfiberboy 

Yes, all CoMo tandems are now Gates belt compatible, meaning 28.5" BB spacing. I think that the 28.5" standard came first and then Gates built their belts to that standard. I'm not sure about that though. That spacing does seem to be a good compromise between aero and stoker comfort. One can't go by the top tube length on a single because the stoker stem of course brings the stoker bars aft of the captain's seat tube, not forward.

LV2TNDM

The flipside to the OP's concerns are an irrational obsession with standover height. I've seen 5' 10" guys on 16" mountain bikes because some nitwit told them how "really, REALLY important standover height is!" When you compromise fit and ergonomics for some crazy obsession with top tube clearance, you've lost the battle.

Do you spend hours ON your bike riding it, or standing over it? Comfort ON the bike is paramount.
And if you do come off, how much difference will two whole centimeters make? Not much. And with sloping top tubes, a frame two centimeters smaller DOESN'T have two centimeters more clearance at the front of the top tube. The difference is usually nominal, so you aren't getting really any benefit at all.
And crashing at speed? Two cm of top tube clearance isn't gonna make a bit of difference.

But cycling for hours on end on the wrong size bike will suck.

So don't compromise fit for standover. Especially for a stoker, who, as mentioned, isn't on and off the bike much at all compared to the captain. But yes, "the stoker is always right," so be sure to address concerns. But don't pursue some magical standover clearance minimum because you were told "you're supposed to have it."

I've been riding a mountain tandem with nominal TT clearance for 25 years. Then I added a 6" travel fork and now have no clearance. Do I care? Not at all. Never had an issue. Had two kids. Perfectly functional "down there."

So my advice is to make on the bike fit the top of your criteria. Then standover clearance.

cyccommute 

Your premise is incorrect. Standover height is an important parameter to consider that gets short shrift from a lot of people. If you don’t think standover is important, buy a bike that has limited standover for you and see how well it “fits”. Bikes are just random collections of measurements where you can pick and choose what length of top tube or reach distance or stack or any other measurement you care to consider. They are all interconnected and if the stand over is off, the rest of the bike will be ill fitting as well.

As for someone riding a frame that is far too small for them, I’ve seen that too. I doubt, however, that it is do those someone saying hat standover is “really, REALLY important”. It’s more likely to do with the rider’s background and if they rode BMX into their teen years or with the availability of bikes or just inexperience with choosing a bike. I really doubt that any competent shop would sell someone a bike that is several sizes too small because they want the customer to have extreme amounts of standover clearance.

As I said above, if you can’t get on the bike comfortably, you can’t ride it comfortably. It goes back to the fact that geometry for the entire bike is related. A bike which is too tall will be too long. If the rider has to stretch to get on the bike, they are likely to have to stretch to reach the bars. That’s not going to be comfortable when you spend hours ON the bike looking like Superman to reach for the bars.

My wife would like to talk to you about how painful it is to have to bail off a bike when you don’t have those “two whole centimeters” or, more precisely, when you have an extra 7 to 10 cm to deal with. As I’ve suggested before, go out and get a bike that is anywhere from 3 to 5 sizes larger than what you ride now and report back to us about how comfortable it is.

If the bike is far to large…like 7 to 10 cm…control of the bike is a whole lot different. While it is true that standover won’t make that much difference in a crash, the other, related, parameters will make a difference in the control of the bicycle.

Yup. So why do suggest putting small people on bikes that are far to big for them? A bicycle that is too big is just as uncomfortable…no, it’s more uncomfortable…as a bike that is too small. Again, go try it yourself.

The quote is “the stoker never makes a mistake”.

But, like so many others, you are telling the stoker that they should just settle for what they get. And, while the stoker may remain seated most of the time, they don’t necessarily want to remain seated all the time. They may want to get off the saddle occasionally. Not necessarily off the bike but just stand still for a couple of minutes. If you get off a padded saddle and onto an unpadded frame tube, that’s not an improvement.

You are making a mistake that so many make. They seem to think that bike fit is everything but standover. Bike fit is everything…including standover. And standover is more important for small riders because the bikes that they have available to them are usually too tall to begin with. You are also making the mistake of thinking that fit is only important for the captain. Tandem riding is a team sport. Both members of the team have to be comfortable. Telling one member of the team that they can “just get used to it” isn’t exactly in a team spirit, now is it?

cyccommute 

Don’t take this the wrong way but your picture illustrates…or, better yet, fails to illustrate…the issue that a tandem team with a large size difference has. I don’t have pictures of my wife and I on a tandem…I tend to avoid cameras…but from your picture, you can see that you and your wife’s heights aren’t all that different. The top of her head is only slightly below yours. When you look in your helmet mirror, you can probably see her face. When I look in my mirror, I barely see the top of her helmet. She is a full foot shorter than I am and in bare feet, the top of her head barely comes to the bottom of my chin. jnbrown’s picture (post 23) is closer to our team’s size disparity but only somewhat. themrbruceguy’s team’s size difference is the same foot of height difference as my wife and I. In all honesty, my wife is small enough that she could almost use a kid crank on a “normal” sized tandem.

That kind of size difference along with the petite size of the stoker introduces challenges on finding the right sized tandem.

LV2TNDM

My point that standover has been the dominant parameter that people focus on IS my point. This is my premise and it's spot-on. And if you disagree, then fine. But 20 years in the industry on the west coast has provided enough evidence to support my assertion. Disagree all you want, but this is my experience. And that's why I would see so many people on bicycles that fit them terribly while riding the bike, all in an effort to get some "magical" standover clearance.


In fact, standover clearance wasn't this big deal until mountain bike sales really took off. Customers were convinced that such a problem existed since everyone was convinced they'd be riding "really, really EXTREME terrain," so they bought small bikes. Then that approach started being applied to road bike fitting, despite it not being any big deal for the century preceding the advent of mountain bikes. Somehow, people were terrified of their top tubes! OMG, it's gonna GET YOU!


Oh, and despite your opinion that, "Bikes are just random collections of measurements," they are nothing of the sort! Bicycle frames are designed as a unit, with all tube lengths chosen for a specific frame size, based on AVERAGE body dimensions for the general riding public. Random? My god, no!


The fact that you've gone to great length to rebut my post indicates that you will not be convinced otherwise. Again, I've had enough experience at the retail and manufacturing level that I know what I've observed and learned over the years. And I've also come to be able to quickly identify a "difficult" customer who will NEVER be happy. I'm pretty sure you fall in that category. Which is why I'm SO HAPPY to not have to deal with that crap "professionally" any more.


To YOUR specific issue(s): there's simply NO WAY you'll be happy with anything off the shelf. This much is clear. Go visit a reputable custom tandem builder and have something built for your specific needs. With detailed body measurements from you and your stoker, there's no reason why you shouldn't find the PERFECT solution. That said, I'd sure love to learn in the future if you're actually ABLE to find the perfect bike. Honestly, I'd be VERY surprised to find you a satisfied customer.


And did you not actually READ my post? I just said that I ride a mountain tandem with ZERO standover clearance and it fits fine. 25 years riding it happily, from Trail 401 in Crested Butte, to Hermosa Creek in Durango, Moab's Slickrock Trail, Donner Pass's Hole in the Ground, to many other technical challenges. Again, never have I had issue with the standover clearance. But then again, I hail from the mid 80's on mountain bikes, so I'm used to a more "vintage" approach to fit. So that kinda proves your silly assertion wrong. Bike fits great. But then again, when I'm riding, I never seem to get a nagging feeling or doubt about "not having a WHOLE LOT OF CLEARANCE over the top tube," so I'm never second-guessing myself.


Who said 7-10 cm too large? You must have interpreted 2 cm to be five times that amount! Why on earth would you conclude that I'm advocating for a rider to choose something so completely beyond their size range? I never said that and for you to conclude same indicates some serious reading comprehension problems. To be clear, the rider considering a 56cm road bike who's overly obsessed with standover clearance gives up ideal fit that the 56 provides and instead chooses a 54cm. Result? Cramped cockpit. But the bike's bought and ridden, so the rider is then forced to compensate for the cramped cockpit with a longer stem. Now his front-center is off; weight too far forward. Then he realizes that the saddle's too far above the bars for comfortable riding, so he now has to consider a riser stem. Or a new fork with longer steerer tube. Again, all for a whole .8 inches of clearance over that terrifying top tube! That's complete lunacy. Life and death won't be determined by that measly .8 inch! But good fit will be negatively affected.


And you're saying that having a top tube .8" higher than what it is would permanently physically and emotionally damage your stoker? I find that hard to believe. And if it's true, than that's probably more the result of listening to your rather than a qualified bicycle fitter!


All I can say at this point is good luck, you're gonna need it.

jccaclimber

I'm starting to remember why I decided to spend my time in other forums so many years ago.

KC8QVO

Excellent post. I've been trying to figure this out with my girlfriend for a while now - you articulated what I have determined, but never put in to words. I'm entertaining the idea of a tandem for a variety of reasons, in short - it would keep us "together" on rides (she's slower and bonks fast, hard to do any miles). She's short and has something in her head that she needs to rest her feet on the ground sitting in the saddle when she's stopped. I've tried to fight that one to fix her obvious fitment issue on her single (not getting proper leg extension = saddle too low) but the "fear factor" shoots up and she's afraid of the bike not being able to plant her feet on the ground. Saddle vs top tube to base "stand over" are two vastly different points, but I think "fear of the bike" is the same. If anyone is afraid of some aspect of it the result is the same - they are uncomfortable and don't enjoy. How do you conquer the fear and get proper fitment? That challenge increases with sizing that is a bit outside of the "norm".

Carbonfiberboy 

Yes, we are both short. My wife is 5'1" and uses 151mm cranks. I'm 5'6", 2" shorter than I used to be. In HS, I never understood why the captain of the basketball team dated girls who were 5'2" Teams with a 1' difference in height are thus quite common. That's the reason for the popularity of the CoMo Periscope tandem.



I see that it's possible that there might be a misunderstanding in this thread of the definition of standover height. Having "standover" in bike fit terms means being able to stand flat-footed on the ground in front of one's saddle. Period. If the captain did not have standover, it would be impossible for him to steady the bike while the stoker mounted and clipped in. The usual description of "holding the bike steady" is that the captain should have both feet firmly planted as far apart as standover allows, the saddle nose pressing into his lower back, and the top tube braced against his inner thigh. On our bike as pictured in post 28, I can just barely put one finger between my pubic bone and the top tube. But that's enough.

OTOH, the stoker doesn't really need standover to operate the bike, just the proper pedal to saddle fit distance. However, there will be occasional extended stopped periods where the captain will want to come off the saddle and put down both feet, partly for comfort, partly for safety. At those times, the stoker will really appreciate the wise choice of bicycle which permits her to come off the saddle and stand with both feet on the ground, straddling the top tube without pain in her crotch. That's what stoker standover is and why it's a really good idea.

This isn't complicated and is easily obtained. I can't figure out what all the fuss is about. I have ridden with many, many tandem teams, attending a tandem rally with over 400 bikes, and I think every one had standover for both riders. I think that because we had a mass start ride which took quite a while to assemble and get going. Tandem rallies are all about looking at other teams and their bikes and are great fun.
"

cyccommute 

Since you have experience in the industry (assuming retail), what is the first thing you ask when someone comes into a shop to buy a bike? Do you ask them what their reach is? What top tube length they need? What stack they need?

Every shop I’ve ever been to starts with having a customer stand over the bike, lift the bike, and see how much clearance the rider has. That is standover! It’s also a quick way to get close to a proper size. They then move on to having the rider get up in the saddle and check the reach to the handlebars but every shop I’ve been to starts with having the customer stand over the bike. Even at my co-op, that’s were we start on any bike.

I‘ve been buying bicycles since the late 70s. I’ve purchased 40 of them for myself (22 mountain bike vs 18 road bike) and another couple of dozen for my wife as well as 10 or 15 for my kids. Again, every bike shop I’ve been to for that most of 4 decades has started with having me (or my wife or my kids) stand over a bike before considering any other parameter.

People didn’t “buy small bikes” when they bought mountain bikes. Manufacturers made mountain bikes smaller. The proportions for mountain bikes are made so that you ride a smaller frame. If you ride a 58cm (23”) road bike, a 19” to 20” mountain bike is proportioned to your size. If you tried to ride a 23” mountain bike, the top tube as well as the standover would be wrong. It would be a horrible ride.

Frames of a given size have become shorter over time because the bikes are being made with sloping top tubes but there are a couple of good reasons for that. Having a 100 or 120mm or more suspension fork on a bike pushes the front of the bike upward meaning that the rider needs more standover so the frame is made smaller. Making the frame smaller by sloping the top tube also adds lateral stiffness to the frame so that the bike isn’t whippy. But even with a shorter seat tube, the bikes are still have the same proportionalities as when they used longer seat tubes. A 20” mountain bike many only have a 15 to 18” seat tube but it still has the same top tube length as well as stack and reach.

Say what?! I said no such thing. I said exactly what you just said. You can’t ignore standover because it is as much a part of the geometry of the bike as top tube length, stack, reach or any other parameter you want to list. They don’t even vary that much from manufacturer to manufacturer. A 52 cm bike from one manufacturer will have very similar parameters to another manufacturer’s frame of the same size.

Nope, not a difficult customer at all unless someone tries to convince me that what I know I need isn’t what I need. Even then I’ll walk out of a shop rather than argue with someone. I’ve been buying and riding bikes for nearly 50 years now. I know what frame will fit me and have bought several frames and bikes without riding them and have had zero issues. I bought the Cannondale tandem off Fleabay, drove from Denver to Bakersfield, CA to pick it up, packed it in my car, and drove back home before riding it. The only changes I made to my part of the bike was a slightly longer stem and different handlebars. It fits exactly like my Cannondale T1 of the same age (and the same color).

I had to make several changes to the stoker position but far less than I’ve made to other tandems I’ve owned. The “difficult” member of the family to fit a bike is my wife but that is because she is petite in a world that doesn’t recognize that she exists. She has swung a leg over many a bike and has rejected dozens just on that factor alone. She hasn’t even taken them out into the parking lot because she knows what is comfortable.

Even then she will be polite and courteous to a sales person unless that sales person tries to convince her that she’ll “get used to the bike”. She knows from long…and very painful…experience that “about right” isn’t right.


Perhaps you should read up post a little. Me, myself, I am perfectly happy with anything off the shelf as long as it is my size (58 cm road, 19” to 20” mountain). I can go to any shop in the world, point to a bike and say “I’ll take that one”, and go ride it for hours on end without modifying it. My wife, not so much. Most shops won’t have what she needs and most companies won’t even make what she needs.

As to the tandem, again, read up thread. I’ve found the PERFECT solution. Not many companies make a tandem in the proportions that Cannondale did in their 2010 L/S tandem. When my wife started getting the tandem bug, I was afraid that we’d have to settle for something that was far to large for her as a stoker. We didn’t. She has plenty of room and is very comfortable on a bike that has a huge front for me and a very tiny stoker compartment for her.

Great for you. I really doubt that “zero clearance” is a “zero” as you make it out to be. I also doubt that your clearance would go into negative numbers which is what many very small stokers are asked to live with.

You seem to be missing the point here. The discussion that I’m having is about the stoker, not the captain. I’m also talking about particularly petite stokers. Finding a bike that is too big for them isn’t an issue. I wish that small riders had the dilemma you present. Their problem is never with finding a bike that is too small or too cramped.

themrbruceguy has a similar problem to mine. His stoker, like mine, is a foot shorter than he is. Finding a bike that fits him isn’t the issue. Finding a tandem that fits her is. Most of the tandems he is looking at are classic 58/50cm frames. At 5’2”, his wife is likely stretching it to ride a 50cm bike. My 5’6” daughter comfortably rides a 50cm bike. My wife is 5’ tall and rides a 43 cm bike. A 49cm is 7 cm too tall for her and I would hazard a guess that the themrbruceguy’s wife would be closer to that 43cm bike than a 49cm.

That was my point. If you think that someone should be riding a bike that is 7cm taller than they should, how about putting your sensitive bits to the test? Get a bike that is 7 cm taller (almost 3 sizes bigger) and go ride it. Report back to us how your sensitive bits do. I won’t do it myself nor would I ask my wife to do it (anymore). I’ve had the chance to get a Cannondale touring bike that was the next size up from what I currently use and I passed on it. It would have been too uncomfortable.

My wife…and probably every other petite rider out there…haven’t had that choice. They have had to ride bikes that are too large if they want to ride at all. They can’t “ride all day in comfort” because they can’t start in comfort.


Again, not 0.8”. More like 3” to 4”. Is that enough for you? Would that be “terrifying” enough for you? My wife has lived that and more. She has had to ride a bike where not only could she not stand flat footed over the bike but there was probably 4” between her feet and the ground. She had to hook a leg over the top tube just to stop at a light. It’s a wonder that she rides a bike at all.

Not luck at all. I’ve got knowledge and experience. I don’t need “luck”.

VegasTriker

Too bad you don't live closer to Madison Wisconsin or you could try out a used Rans Screamer recumbent tandem. The difference in height between the two riders is less of an issue because you move the seat back or forward to adjust for different heights. Unfortunately the don't come cheap either. A have a former coworker with a neurological disease that makes walking difficult but he is an avid tandem rider with his wife and the Screamer is the one he rides. https://budgetbicyclectr.com/rans-sc...rt-tandem.html

cyccommute 

First, I would suggest carefully considering your goals when it comes to riding a tandem. You need to have a very frank discussion about your “togetherness” and your need to do more miles while dragging her along. A tandem is ridden by a team for a reason. At the very least, rent or borrow a tandem before you invest a lot of money in one.

As to your girlfriend’s riding style, it may be due to her having been put on bikes that were way too big for her while she was starting to ride. Riding a bike that is too large and that is difficult to control can put fear into someone that is hard to get over, especially if that happened when the rider was younger. Putting her on a tandem and making her trust your judgement rather blindly…the stoker can’t see much ahead of them other than the captain’s back… probably isn’t going to make her any less fearful.

You have to have a lot of patience to help a fearful rider get over their fear. It’s a very long process and isn’t helped if you are pushing for more and harder miles. Sometimes the advice is best delivered by someone outside the relationship.

Carbonfiberboy 

She's probably just afraid of her lack of skill, which can put her in a very dangerous position. My wife got run over by a 1-ton truck on her single about 20 years. It was bad. It was some little bit her lack of skill, but mostly the fear that was engendered by said lack of skill. Of course the driver was really at fault for driving illegally, but a more experienced rider could have avoided the accident. Experienced riders have usually avoided many accidents, which is what experience is all about. You can't learn a new thing without a stressor. Anyway, don't tell you SO any of this, this is just for you, so you can better empathize with her. I'm just saying that her fear is not groundless.

The end of the above little tale is that my wife no longer rides her single on the street. She has stoked for me for over 17,000 miles without an issues. She trusts me. Which is kinda weird, being a man and knowing my own fallibility but love is a wonderful thing. I try to earn that trust on every ride. When one has been riding bikes in traffic since being 8 years old, correct reaction is built into one's spine.

cyccommute 

Now with pictures. We have ridden tandems that are larger on the rear but my wife did struggle to get over the top tube to mount. She has always mounted a bike by putting her leg over the top tube. The extremely low top tube on this bike makes that kind of mounting easier.



She has plenty of room to stand over the frame.




She prefers putting a foot down on starts and stops. With this size frame it’s not an issue.




Not the size difference. Carbonfiberboy’s stoker can look over his shoulder. She looks right in the middle of my back.



All in all, it’s far better to have a happy stoker. If the bike fits, they are a whole lot happier.

KC8QVO

Thanks for the pictures.

Would you mind sharing what your wife's inseam measurement is and what the "stand-over height" is on the bike? I see the top tube is angled quite a bit. Maybe get a range from the nose of the saddle to where the stoker bars overhang?

cyccommute 

Her inseam is 28”. The published standover for the extra large/small is 27.6” From the nose of her saddle to the rear of mine, is 17” while the distance from the nose of her saddle to the handlebar is 13” with about 2.5” of adjustment on the stoker stem.